1. Field of the Invention
The present invention relates to a semiconductor device and to a method of fabricating the same. More particularly, the present invention relates to a contact of a semiconductor device and to a method of fabricating the same.
2. Description of the Related Art
A typical semiconductor device includes several layers of circuitry, an insulating layer interposed between the layers, and contacts that extend through the insulating layer to connect the different layers of circuitry. Conventionally, photolithography has been used to remove portions of the insulating layer and form contact holes. These holes are then filled with conductive material to form the contacts. However, in recent years, the spacing between such contacts has been decreased to meet the demand for more highly integrated semiconductor devices. Moreover, the resolution provided by conventional photolithography technology is not sufficient to produce the finer contacts required of today's highly integrated semiconductor devices.
However, fine features of a semiconductor device can be formed through the use of spacers as disclosed in U.S. Pat. No. 6,063,688. More specifically, in this method, a first spacer is formed on a region of a semiconductor substrate. Then, a second spacer having a thickness less than that of the first spacer is formed on the sidewalls of the first spacer, and the first spacer is removed. This process is repeated until the spacing between the sidewalls of the spacer corresponds to the desired dimension of the feature to be formed.
Although the method disclosed in U.S. Pat. No. 6,063,688 can be used to form a pattern of fine lines, the method cannot be used to form a pattern of contact openings. Furthermore, the process of forming one of the spacers may damage the underlying semiconductor substrate. Furthermore, the method cannot be used to realize a structure having various types of contacts such as a memory device having both a contact for a capacitor lower electrode and a contact for a bit line.